Engine valve train system

Abstract

An engine valve train system for selectively effecting operation of a pair of side by side valves of a cylinder and to effect deactivation of one of the valves in the pair during predetermined modes of engine operation includes first and second rocker arms pivotably supported on a hollow rocker shaft which in turn is suitably supported for pivotable movement between an operative position and an idle or inoperative position and which is connected to a source of pressurized hydraulic fluid. The first rocker arm is adapted to be driven by an actuator to effect opening and closing movement of one of the valves. The second rocker arm has a hydraulic cylinder and piston means which, when the rocker shaft is in the operative position, is supplied with hydraulic fluid whereby to extend the piston to operatively connect the second rocker arm with the first rocker arm so as to be also operated thereby whereby to effect opening and closing movement of the other one of the valves and when the rocker shaft is in the idle or inoperative position, hydraulic fluid can drain from the hydraulic cylinder and piston means whereby the second rocker arm becomes inoperative to effect opening movement of the other one of the valves.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A reciprocating internal combustion engine of the type having an engine block means defining at least one cylinder with an associate pair of ports, a valve located for axial movement in each of said ports with each said valve normally biased to a valve closed position relative to its associate port, rocker shaft support means fixed to said engine block means, and a valve actuator spaced from said valves and operable to effect reciprocation of said valves, the improvement comprising: a rocker shaft pivotably supported by said rocker shaft support means, said rocker shaft having an axial passage adapted to be in continuous flow communication with the pressurized lubricant supply of the engine; a first rocker arm pivotably supported on said rocker shaft in position for engagement with said valve actuator and with one of said valves and actuated in rocking movement whereby it can operate to effect opening and closing movement of said one of said valves, and a second rocker arm pivotably supported on said rocker shaft next adjacent to said first rocker arm and operatively engaging the other one of said valves, said second rocker arm having a hydraulic cylinder means therein, a piston sealingly journaled in said hydraulic cylinder means and located so as to permit engagement of said piston with said first rocker arm, said second rocker arm having a supply/drain passage means therein to said hydraulic cylinder means, and a drain passage which extends to the exterior of said second rocker arm and which is located in circumferentially spaced apart relationship to said supply/drain passage means, said rocker shaft having at least one radial riser supply passage in flow communication with said axial passage and a chordal exterior drain groove circumferentially spaced from said supply passage both said radial riser supply passage and said chordal exterior drain groove being axially located on said rocker shaft so as to be in radial alignment with said supply/drain passage means and with said drain passage in said second rocker arm; and, drive means operatively connected to said rocker shaft to effect pivotable movement thereof between a first position at which said supply passage is in flow communication with said supply/drain passage means whereby pressurized lubricant can be supplied to said hydraulic cylinder to effect movement of said piston in a direction whereby said second rocker arm will be operatively driven by said first rocker arm, and a second position at which said supply passage is out of flow communication with said supply/drain passage means and said drain groove is in a position to effect flow communication between said supply/drain passage means and said drain passage whereby said second rocker arm will be operatively disconnected from said first rocker arm. 
     
     
       2. A reciprocating internal combustion engine of the type having an engine block means defining at least one cylinder having an associate pair of ports, a valve located for axial movement in each of said ports with each said valve normally biased to a valve closed position relative to its associate port, rocker shaft support means fixed to said engine block means, and a valve actuator spaced from said valves and operable to effect reciprocation of said valves, the improvement comprising: a hollow rocker shaft pivotably supported by said rocker shaft support means, said rocker shaft having an axial passage adapted to be in continuous flow communication with the pressurized lubricant supply of the engine; a first rocker arm pivotably supported on said rocker shaft in position for engagement with said valve actuator and with one of said valves whereby it can operate to effect opening and closing movement of said one of said valves, a second rocker arm having a bearing bore extending transversely therethrough by means of which said second rocker arm is pivotably supported by said rocker shaft and having a driven arm portion operatively engaging the other one of said valves, said second rocker arm having a hydraulic cylinder means therein, a piston journaled for axial movement in said cylinder means and having a rod portion thereof adapted to engage said first rocker arm, said second rocker arm having a supply/drain passage means therein which extends from said bearing bore therein to said hydraulic cylinder means, and a drain passage which extends from said bearing bore to the exterior of said second rocker arm and which is located in circumferentially spaced apart relationship to said supply/drain passage means, said rocker shaft having at least one radial riser supply passage in flow communication with said axial passage and a chordal exterior drain groove circumferentially spaced from said supply passage, said supply passage and said drain groove being axially located on said rocker shaft so as to be in radial alignment with said supply/drain passage means and with said drain passage in said second rocker arm; and, drive means operatively connected to said rocker shaft to effect pivotable movement thereof between a first position at which said supply passage is in flow communication with said supply/drain passage means whereby pressurized lubricant can be supplied to said hydraulic cylinder means to effect movement of said piston in a direction whereby said second rocker arm will be operatively driven by said first rocker arm, and a second position at which said supply passage is out of flow communication with said supply/drain passage means and said drain groove is in a position to effect flow communication between said supply/drain passage means and said drain passage whereby said second rocker arm will be operatively disconnected from said first rocker arm. 
     
     
       3. A reciprocating internal combustion engine of the type having an engine block means defining at least one cylinder with a pair of side by side ports associated therewith, with each such port having a valve located for axial movement relative thereto with each said valve being normally biased to a valve closed position relative to its associate port, rocker shaft support means fixed to said engine block means, and a valve actuator spaced from said valves and operable to effect reciprocation of said valves, the improvement comprising: a rocker shaft pivotably supported by said rocker shaft support means, said rocker shaft having an axial passage adapted to be in continuous flow communication with the pressurized lubricant supply of the engine; a rocker arm means pivotably supported by said rocker shaft in position for engagement with said valve actuator and with said valves, said rocker arm means including a first rocker arm having a bearing bore extending transversely therethrough receiving said rocker shaft, a drive arm portion operatively engaged by said valve actuator and a first driven arm portion operably engaging one of said valves, and a second rocker arm having a bearing bore extending transversely therethrough by means of which said second rocker arm is pivotably supported by said rocker shaft and having a second driven arm portion operatively engaging the other one of said valves, said second rocker arm having a hydraulic cylinder means therein, a piston means journaled for axial movement in said cylinder means and having a rod portion adapted to engage said first rocker arm, said second rocker arm having a supply drain passage means therein which extends from said bearing bore therein to said hydraulic cylinder means, and a drain passage which extends from said bearing bore to the exterior of said second rocker arm and which is located in circumferentially spaced apart relationship to said supply/drain passage means, said rocker shaft having at least one radial riser supply passage in flow communication with said axial passage and an adjacent chordal exterior drain groove circumferentially spaced from said supply passage, said radial riser supply passage and said chordal exterior drain groove being axially located on said rocker shaft so as to be in radial alignment with said supply/drain passage means and with said drain passage on said second rocker arm; and, drive means operatively connected to said rocker shaft to effect pivotable movement thereof between a first position at which said supply passage is in flow communication with said supply/drain passage means whereby pressurized lubricant can be supplied to said cylinder to effect movement of said piston in a direction whereby said second rocker arm will be operatively driven by said first rocker arm, and a second position at which said supply passage is out of flow communication with said supply/drain passage means and said drain groove is in a position to effect flow communication between said supply/drain passage means and said drain passage whereby said second rocker arm will be operatively disconnected from said first rocker arm.